The objective of the present phase is to evaluate the relationship between administration of diazepam and ibuprofen and the clinical symptoms, psychological state and neurohumoral responses of patients with Tempromandibular Pain Dysfunction Syndrome (MPD). Subjects with MPD are administered diazepam, ibuprofen, diazepam and ibuprofen or placebo for a 4-week period. Pain and mandibular function are evaluated as well as the effect of treatment on anxiety and depression. Beta-endorphin and cortisol levels are being assessed from blood samples of these patients. These data are analyzed to determine the effect of the drugs used.